Technical Field
The present disclosure relates to a vertical slide backwash valve, and, more specifically, to a vertical slide backwash valve for reversing fluid flow through a filter body.
Related Art
Swimming pools and spas generally include water filters for cleaning the pool/spa water during circulation. Typically, these water filters include a filter body containing a filter media, such as sand or diatomaceous earth (DE). It is necessary to periodically reverse the fluid flow through such filters to clean and/or flush the media to a waste location where the flushed water is expelled to. This activity is referred to as backwashing. To facilitate switching the filter between the standard operating mode, e.g., “filter mode,” and the “backwash mode,” a backwash valve can be provided on the filter that alters the flow path of water based on the desired mode.
FIG. 1A is a perspective view of an exemplary DE filter 2 with a vertical slide backwash valve 4 of the prior art. The vertical slide backwash valve 4 is generally mounted on the side of the DE earth filter 2, and can have a narrow, vertical form. Alternatively, a filter may have a multiport backwash valve attached thereto, which is generally bulkier and can be mounted on the top or side of a filter body. For example, FIG. 1B is a perspective view of a sand filter 6 with a top-mounted multiport backwash valve 8 of the prior art, while FIG. 1C is a perspective view of a sand filter 10 with a side-mounted multiport backwash valve 12 of the prior art.
To categorize backwash valves, one might look to how a user operates the valve handle and the movement of the valve. For example, exemplary categories can generally include sliding valves, rotating valves, etc. Sliding valves are generally compact and can have a lower cost compared to rotating valves, but might not be very hydraulically efficient. In contrast, rotating valves can be hydraulically efficient due to a line-of-sight straight-through flow path when in filter mode, but generally can be larger and have a greater cost when compared to sliding valves. Some sliding valves and rotating valves can utilize seals generally made of rubber to prevent leaking from the waste port during filter mode. However, when the valves are actuated between filter mode and backwash mode, the seals can generally experience sliding friction that causes wear. Accordingly, lubricant might be applied to the seals. However, applying lubricant to the seals can, in some instances, damage the seals because it can cause dirt and debris to attach to the seals, which generally further accelerates the wear.
FIGS. 2A-2D demonstrate the vertical sliding backwash valve 4 of FIG. 1A in greater detail. FIG. 2A is a side elevational view of the vertical sliding backwash valve 4. The vertical sliding backwash valve 4 includes a body 12, an end cap 14, a waste outlet 16, a handle 18, a stem 20 (shown in FIGS. 2C-2D), and a spool 22 (shown in FIGS. 2C-2D). The body 12 includes a first end 24, a second end 26, a central tube 28, a first pool port 30, a second pool port 32, a first filter port 34, and a second filter port 36. The end cap 14 is connectable to, and forms a fluid tight seal with, the first end 24, while the waste outlet 16 is connectable to, and forms a fluid tight seal with, the second end 26. The first and second filter ports 34, 36 can each include a nut 38 that is engageable with a port of a filter to secure the first and second filter ports 34, 36 with the filter's ports. The first and second pool ports 30, 32 are connectable with the fluid circulation system of a pool/spa. Specifically, the second pool port 32 can receive fluid from the pool/spa while the first pool port 30 can return fluid back to the pool/spa. The pool/spa water can be provided to the second pool port 32 by a pump, for example.
FIGS. 2C-2D are sectional views of the vertical sliding backwash valve 4 showing the interior of the vertical sliding backwash valve 4. As shown in FIGS. 2C-2D, the spool 22 is connected with the stem 20, which extends through the end cap 14 and is connected with the handle 18. The spool 22 includes a first piston 40 and a second piston 42 connected by a tie-bar 44. The first and second pistons 40, 42 each include an o-ring sealing gasket 46 for creating a seal radially outward against the body 12. The backwash valve central tube 28 defines a general housing chamber 48 for the spool 22. The general housing chamber 48 can be divided into a plurality of sections. Namely, the general housing chamber 48 includes a first end section 50, a first central section 52, a second central section 54, a third central section 56, and a second end section 58. The first end section 50 spans the first pool port 30 and extends to the end cap 14. The first center section 52 spans the first filter port 34. The second center section 54 spans the second pool port 32. The third center section 56 spans the second filter port 36. The second end section 58 extends from the bottom of the second filter port 36 to the waste outlet 16.
FIGS. 2C-2D illustrate the vertical sliding backwash valve 4 in a configuration for connection with a typical DE filter port configuration. That is, the vertical sliding backwash valve 4 is configured for attachment with a filter body that has a filter inlet port below a filter outlet port. The vertical sliding backwash valve 4 of FIGS. 2C-2D could be configured for attachment with a filter that has a filter inlet port above a filter outlet port, which can be, for example, a sand filter. In such a configuration, the first pool port 30 would function as the waste port, and the waste outlet 16 would return fluid back to the pool/spa.
FIG. 2C is a sectional view of the vertical sliding backwash valve 4 showing the flow-paths when in filter mode. When in filter mode, the handle 18 is pushed down, causing the stem 20 to drive the spool 22 further into the central tube 28. The handle 18 can include a twist lock mechanism that secures the handle 18 in the filter mode position, e.g., pushed down. When the handle 18 is pushed all the way down and two flow paths are created. The first flow path A extends from the first filter port 34, across the first central section 52 and the first end section 50, and to the first pool port 30. The second flow path B extends from the second pool port 32, across the second central section 54 and the third central section 56, and to the second filter port 36.
When in filter mode, pool/spa water is provided to the vertical sliding backwash valve 4 at the second pool port 32 by the pool or spa's water circulation system and flows along arrow B to the second filter port 36. The water exits the vertical sliding backwash valve 4 at the second filter port 36, where it enters a filter. The water traverses the filter, where it is filtered, and is returned to the vertical sliding backwash valve 4 at the first filter port 34 and flows along arrow A to the first pool port 30. The water exits the vertical sliding backwash valve 4 at the first pool port 30, where it is recirculated to the pool/spa. As such, when in filter mode, the pool/spa water travels in two S-like flow paths, e.g., arrows A and B. In this configuration, the spool 22 is retained in the filter mode position by the locking mechanism of the handle, and the friction of the piston seals, e.g., the o-ring gaskets 46. The S-like flow path of the water results in hydraulic inefficiencies, e.g., there is a resistance to water flow and a greater than desired pressure-drop. Further, when the o-ring gaskets 46 begin to wear from the friction created every time the pistons 40, 42 are moved by the handle 18, water may be lost through the radial seal of the second piston 42 where it can leak out from the waste outlet 16.
FIG. 2D is a sectional view of the vertical sliding backwash valve 4 showing the flow-paths when in backwash mode. When in backwash mode, the handle 18 is pulled up, causing the stem 20 to pull the spool 22 towards the first end 24 in the central tube 28. The handle 18 can include a twist lock mechanism that secures the handle 18 in the backwash mode position, e.g., pulled up. When the handle 18 is pulled all the way up two flow paths are created. The first flow path C extends from the second pool port 32, across the second central section 54 and the first central section 52, and to the first filter port 34 for backwashing the filter. The second flow path D extends from the second filter port 36, across the third central section 56 and the second end section 58, and to the waste outlet 16.
When in backwash mode, pool/spa water is provided to the vertical sliding backwash valve 4 at the second pool port 32 by the pool or spa's water circulation system and flows along arrow C to the first filter port 34. The water exits the vertical sliding backwash valve 4 at the first filter port 34, where it enters a filter. The water traverses the filter in a reverse manner to the filter mode, thus backwashing (removing) waste from the filter. This waste water is then returned to the vertical sliding backwash valve 4 at the second filter port 36 and flows along arrow D to the waste outlet 16. The water exits the vertical sliding backwash valve 4 at the waste outlet 16, where it is removed from the pool/spa system. As such, when in backwash mode, the pool/spa water travels in two curved flow paths, e.g., arrows C and D. In this configuration, the water pressure, due to the flow direction and pattern, retains the spool 22 in the backwash mode position.
The above-described prior art thus has S-shaped flow paths both in filter mode and backwash mode. Moreover, the radial seal of the pistons 40, 42 can wear over time.
The present disclosure overcomes one or more of these and/or other drawbacks and/or disadvantages of the prior art.